The present invention relates to switching networks of the type in which each of at least four nodes can be connected to every other node in the system by an interruptable current branch.
Such a switching network is disclosed, for example, in U.S. Pat. No. 4,247,787. In networks such as this, four nodes are provided, each of which is connected via an interruptable current branch to each of the remaining three nodes. The six interruptable current branches required for this purpose connect the four nodes in four partial rings, each of which is provided with three nodes. In each case any two partial rings have two nodes in common. Since each node can be connected to or isolated from three different nodes via three different current branches, in the case of a failure of a switching system provided in one of the current branches, two further intact current branches still remain which ensure that the node affected by the failure of the switching system is connected to the other nodes. If thereafter one of the switching systems provided in the two current branches fails, the supply of current to the affected node is guaranteed because of the functional reliability of the third remaining switching system. However, such networks can only be expanded with a relatively large expenditure or with considerable loss of redundancy and, in this form, lead to complex network structures which are difficult to understand.